The present application relates to electrical power, and more particularly, but not exclusively, to charging electrical energy storage devices.
Electrical energy storage devices are used in a variety of applications. In some implementations, these storage devices take the form of an electrochemical battery or bank of such batteries configured with a charger. To accurately control charging current, it is important to determine the battery voltage at the battery terminals. Because the voltage usually differs from one end of the battery cable to the other due to cable impedance, there can be a non-negligible voltage drop along the cable for typical current and voltage levels. Standard battery chargers sometimes address this problem by including separate “sense” lines from the battery terminals to a high impedance voltage monitor circuit in the charger. These sense lines are in addition to the battery cable used to charge the battery. Because the impedance of the voltage monitor is relatively high, negligible current flows through the sense lines and the detected voltage is approximately the same as the actual battery voltage. However, sense lines are susceptible to breakage, and result in a more complex wiring arrangement that can cause reliability problems. Alternatively, some have addressed this problem by oversizing the cabling to reduce its impendence at the penalty of extra cost/weight and potentially less precise operation. Thus, there remains an ongoing demand for further contributions in this area of technology.